Method of manufacturing an optical device

ABSTRACT

The invention provides an optical device having an optical element, a substrate, and a flexible member. A first portion of the flexible member is disposed so as to be spaced from the substrate, a second portion surrounding the first portion is adhered to the substrate, and a closed space is defined between the first portion and the substrate. The optical element is mounted on the substrate within the closed space.

This is a Divisional of application Ser. No. 09/971,619 filed Oct. 9,2001. The entire disclosure of the prior application is herebyincorporated by reference herein in its entirety.

Japanese Patent Application No. 2000-342907, filed on Nov. 10, 2000, ishereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to an optical device and method ofmanufacture thereof and to an electronic instrument that incorporatesthe optical device.

2. Description of Related Art

An optical device having an optical element, such as a solid stateimaging element, is known. In the packaging of a conventional opticaldevice, the optical element is contained within a container, and ahermetic seal or the like is applied, so that the optical element is notexposed to moisture. In this way, a conventional optical device isprovided with an expensive container to which a hermetic seal or thelike is applied, and therefore tends to have a high cost.

SUMMARY OF THE INVENTION

An optical device of the present invention includes:

a substrate;

a flexible member having a first portion disposed so as to be spacedfrom the substrate, and a second portion surrounding the first portionand adhered to the substrate, in which a closed space is formed betweenthe first portion and the substrate; and

an optical element disposed within the closed space, and mounted on thesubstrate.

An electronic instrument of the present invention incorporates the abovedescribed optical device.

A method of manufacturing an optical device of the present inventionincludes: mounting an optical element on a substrate; adhering aflexible member to the substrate so as to cover the optical element, toform a closed space between the substrate and the flexible member; andevacuating the closed space.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a first embodiment of the optical deviceof the present invention;

FIG. 2 is a sectional view of a second embodiment of the optical deviceof the present invention;

FIG. 3 is a sectional view of a third embodiment of the optical deviceof the present invention;

FIG. 4 is a sectional view of a fourth embodiment of the optical deviceof the present invention;

FIG. 5 is a sectional view of a fifth embodiment of the optical deviceof the present invention;

FIG. 6 is a sectional view of a sixth embodiment of the optical deviceof the present invention;

FIG. 7 is a sectional view of a seventh embodiment of the optical deviceof the present invention;

FIG. 8 is a plan view of an electronic instrument incorporating theoptical device according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiments of the present invention address the problems of theconventional art discussed above. It is an object of the invention toprovide an optical device having a relatively simple construction, so asto be of relatively low cost and to allow a seal. It is also an objectof the invention to provide a method of manufacture thereof and to anelectronic instrument that incorporates the optical device.

An optical device according to the embodiment of the present inventionincludes:

a substrate;

a flexible member having a first portion disposed so as to be spacedfrom the substrate, and a second portion surrounding the first portionand adhered to the substrate, in which a closed space is formed betweenthe first portion and the substrate; and

an optical element disposed within the closed space, and mounted on thesubstrate.

According to the embodiment of the present invention, since the secondportion of the flexible member is simply adhered to the substrate, nocontainer is required, and the optical element can be simply sealedtherein.

In this optical device, at least a part of the substrate may have lighttransmissivity.

In this optical device, the optical element may be mounted on thesubstrate, with an optical portion of the optical element opposing apart of the substrate having light transmissivity.

In this optical device, the flexible member may have a metal foil and anadhesive layer adhered to the substrate.

This makes it possible to obtain an optical device of excellent moistureresistance, noise resistance, and thermal dispersion.

In this optical device, the flexible member may have a water repellentlayer on a surface that is opposite to the side of the closed space.

This makes it possible to enhance the moisture resistance.

In this optical device, the closed space may be filled with an inertgas.

The inert gas can protect the optical element.

In this optical device, a pressure in the closed space may be closer toa pressure in a vacuum than atmospheric pressure.

Since the optical element is in a state that is close to a vacuum, it isnot exposed to moisture.

In this optical device, the substrate may have a hole opening to theclosed space and blocked at a surface that is opposite to the side ofthe closed space.

This configuration makes it possible to utilize the hole to fill theclosed space with inert gas or for evacuation.

In this optical device, the hole that is formed in the substrate may beblocked by a valve.

The valve can be used to maintain the inert gas within the closed spaceor a state that is close to a vacuum.

In this optical device, the hole that is formed in the substrate may beblocked by resin.

The resin can be used to maintain the inert gas within the closed spaceor a state that is close to a vacuum.

In this optical device, the substrate may have a hole that is blocked ona surface on the side of the closed space by the flexible member, andopening on a surface that is opposite to the side of the closed space.

The flexible member can be used to maintain the inert gas within theclosed space or a state that is close to a vacuum.

In this optical device, the closed space may be filled with transparentresin.

The transparent resin can protect the optical element.

In this optical device, the substrate may have a penetrating hole thatis filled with transparent resin.

The transparent resin can be used to maintain the inert gas within theclosed space or a state that is close to a vacuum.

An electronic instrument according to the embodiment of the presentinvention incorporates the above described optical device.

A method of manufacturing an optical device according to the embodimentof the present invention includes: mounting an optical element on asubstrate; adhering a flexible member to the substrate so as to coverthe optical element, to form a closed space between the substrate andthe flexible member; and evacuating the closed space.

According to the embodiment of the present invention, since the flexiblemember is simply adhered to the substrate to evacuate the closed space,no container is required, and the optical element can be simply sealedtherein.

In this method of manufacturing an optical device, evacuation may beperformed through a penetrating that is hole formed in the substrate,and the hole may be then blocked by resin.

The resin can maintain a state that is close to a vacuum within theclosed space.

In this method of manufacturing an optical device, evacuation may beperformed through a penetrating hole that is formed in the substrate,and the hole may be then blocked by a valve.

The valve can maintain a state that is close to a vacuum within theclosed space.

In this method of manufacturing an optical device, evacuation may beperformed through a penetrating hole that is formed in the substrate,and the hole may be then blocked by the flexible member.

The flexible member can maintain a state that is close to a vacuumwithin the closed space.

This method of manufacturing an optical device may further include:

filling the closed space with transparent resin,

wherein evacuation may be performed through a penetrating hole formed inthe substrate, and the hole may be then blocked by the transparentresin.

The transparent resin can maintain a state that is close to a vacuumwithin the closed space.

The embodiments of the present invention will be described withreference to the drawings.

First Embodiment

FIG. 1 shows a first embodiment of the optical device of the presentinvention. The optical device has at least one (one or a plurality)optical element 10. The optical element 10 has an optical portion 12.The optical element 10 may either be a photoreceptor element or aphotoemitter element. When the optical element 10 is a photoemitterelement, the optical portion 12 is a light-emitting portion, and whenthe optical element 10 is a photoreceptor element, the optical portion12 is a light-receiving portion.

In this embodiment, the optical element 10 is an imaging element (imagesensor). If it is a two-dimensional image sensor, a plurality ofphotoreceptors (for example, photodiodes) constituting a plurality ofpixels forms the optical portion 12. If it is a CCD (Charge CoupledDevice) type of imaging element, it has a transfer section (not shown inthe drawings), and the electric charge from the photoreceptor for eachof the pixels is transferred at high speed. As a variant example that isdifferent from this embodiment, the optical element 10 may be a surfacephotoemitter element, and in particular a surface emission laser. Asurface photoemitter element, such as a surface emission laser, emitslight in a direction that is perpendicular to the substrate on which theelement is constituted.

In order to provide electrical connection with the exterior of thedevice, the optical element 10 may have one or more (in this embodimenta plurality) bumps 14. For example, on the surface on which the opticalportion 12 is formed, bumps 14 may be provided to accomplish electricalconnection of the optical element 10 with the exterior of the device.The bumps 14 are provided in positions to allow electrical connectionwith other elements. The bumps 14 preferably project beyond the opticalportion 12.

The optical device has a substrate 20. At least a part of the substrate20 (a part allowing light to pass to the optical element 10) has lighttransmissivity. The substrate 20 shown in FIG. 1 has lighttransmissivity overall, and is, for example, a glass substrate. Aninterconnecting pattern 22 is formed on the substrate 20. Theinterconnecting pattern 22 may have lands formed as regions that arebonded to the optical element 10 or the like. Provided that theelectrical connection is not interfered with, the interconnectingpattern 22 is preferably covered with another element (for example, aresist or the like not shown in the drawings). The interconnectingpattern 22 shown in FIG. 1 is only formed on one surface of thesubstrate 20. However, the interconnecting pattern 22 may be formed onboth surfaces of the substrate 20 and electrically connected by throughholes (not shown in the drawings) or the like.

The optical element 10 is mounted on the substrate 20 with the opticalportion 12 facing the substrate 20 (more precisely a portion havinglight transmissivity thereof). That is to say, the optical element 10 ismounted on the substrate 20 to form a face-down construction. The bumps14 of the optical element 10 and the interconnecting pattern 22 arebonded. If necessary, the optical element 10 and interconnecting pattern22 may be electrically connected by wires (not shown in the drawings).In this embodiment, on the substrate 20, in addition to the opticalelement 10, electronic components 24 and 26 are mounted.

The optical device has a flexible member 30. Tape or a sheet form may beused as the flexible member 30. The flexible member 30 may includemultiple layers. The flexible member 30 shown in FIG. 1 has a base layer34 and an adhesive layer 36. The base layer 34 may have at least one ofthe properties of not allowing moisture to pass (or having highresistance to moisture), of not allowing magnetism to pass, and ofhaving high thermal dispersion. By means of this, an optical device ofhigh moisture resistance, noise resistance, and thermal dispersion isobtained. The base layer 34 may be opaque, enabling light to beprevented from entering the optical element 10. By means of this, anoptical device of low light-induced misoperation is obtained. If thebase layer 34 is a metal foil of aluminum, copper, or the like, theserequirements can be satisfied. The adhesive layer 36 is formed of anadhesive, such as an epoxy resin, an acrylic resin, a silicone resin, orthe like. The adhesive layer 36 may be provided over the entire area ofthe base layer 34, or may only be provided in a part of the base layer34 (for example, the second portion 32 described below).

A first portion 31 of the flexible member 30 is disposed so as to bespaced apart from the substrate 20. The first portion 31 is a portion ofthe flexible member 30 excluding the extremity (for example, the firstportion is defined as the center portion). A region that is surroundedby the second portion 32 (for example, the second portion 32 being theextremity) is the first portion 31. The flexible member 30 includes thesecond portion 32 (for example, the extremity) which surrounds the firstportion 31 that is adhered to the substrate 20. The adhesive layer 36can be disposed on the substrate 20, and the flexible member 30 and thesubstrate 20 adhered by the adhesive layer 36. In this case, theadhesive layer 36 is an inner layer, and the base layer 34 is an outerlayer.

A closed space 40 is defined between the first portion 31 and thesubstrate 20. The first portion 31 and the substrate 20 are preferablyin intimate contact in order to enable the closed space 40 to bemaintained as airtight. The optical element 10 is provided within theclosed space 40. In more detail, surrounding the optical element 10, thefirst portion 31 is adhered to the substrate 20, and the second portion32 covers the optical element 10. It is preferable for moisture to below within the closed space 40. For example, the closed space 40 maycontain a vacuum (Strictly speaking, a state that is closer to a vacuumthan atmospheric pressure. The same applies subsequently.), or may befilled with an inert gas (N₂ or the like). In these environments, theoptical element 10 is protected so as not to be exposed to moisture.According to this embodiment, the optical element 10 can be sealed witha simple construction.

In this embodiment of the optical device, the optical element 10 is aphotoreceptor element, and light which has passed through the substrate20 impinges on the optical element 10. Alternatively, as a variantexample, if the optical element 10 is a photoemitter element, lightemitted from the optical element 10 passes through the substrate 20 andis output.

This embodiment of the optical device is constructed as described above,and the method of manufacture thereof is described below. In thisembodiment, the optical element 10 is mounted on the substrate 20, andthe flexible member 30 is adhered to the substrate 20 so as to cover theoptical element 10. In more detail, the optical element 10 is covered bythe first portion 31 of the flexible member 30, and the second portion32 surrounding this structure is adhered to the substrate 20. Anadhesive may be used for the adhesion of the flexible member 30 and thesubstrate 20. For example, the flexible member 30 may be previouslyprovided with the adhesive. In this embodiment, the adhesive layer 36 ofthe flexible member 30 adheres the flexible member 30 (second portion32) and the substrate 20.

Then, the closed space 40 is formed between the substrate 20 and theflexible member 30. If the flexible member 30 is adhered to thesubstrate 20 in a vacuum, a vacuum will exist within the closed space40. If the flexible member 30 is adhered to the substrate 20 in anenvironment that is filled with an inert gas, the closed space 40 can befilled with an inert gas. The optical element 10 is sealed and protectedwithin the closed space 40. According to this embodiment, the opticalelement 10 can be sealed by a simple process.

The present invention is not limited to the above described embodiment,and various variants are possible. Other embodiments are now described.

Second Embodiment

FIG. 2 shows a second embodiment of the optical device of the presentinvention. This embodiment differs from the first embodiment in that aflexible member 50 has a water repellent layer 52. The water repellentlayer 52 is formed on the opposite surface of a base layer 54 from thesurface on which an adhesive layer 56 is formed. A fluorine coating maybe used as the water repellent layer 52. The water repellent layer 52forms a protective film, and enhances the moisture resistance of theoptical device. The water repellent layer 52 may be such as to be ableto be melted by a laser. In this case, marking is possible.

With respect to the remaining construction, the effect, and the methodof manufacture, this embodiment corresponds to the description of thefirst embodiment.

Third Embodiment

FIG. 3 shows a third embodiment of the optical device of the presentinvention. This embodiment differs from the first embodiment in that theclosed space 40 is filled with transparent resin 60. The transparentresin 60 is provided over the optical portion 12 of the optical element10. The transparent resin 60 need only transmit light to the extent toallow light to be input to the optical element 10 (or lights to be inputfrom the optical element 10). By means of this, the optical element 10is protected by the transparent resin 60. With respect to the remainingconstruction, the effect, and the method of manufacture, this embodimentcorresponds to the description of the first embodiment.

Fourth Embodiment

FIG. 4 shows a fourth embodiment of the optical device of the presentinvention. This embodiment differs from the first embodiment in that ahole 72 is formed in a substrate 70. The hole 72 passes through thesubstrate 70, and opens in the closed space 40. The hole 72 is blocked.Resin may be provided to block the hole 72. The resin 74 may be providedon the opposite side of the substrate 70 from the closed space 40. Theresin 74 may penetrate into the hole 72.

In this embodiment, the closed space 40 contains a vacuum (strictlyspeaking, a state that is closer to a vacuum than atmospheric pressure).For example, by means of the hole 72, the closed space 40 can beconnected to the exterior of the device, and a vacuum created, wherebythe closed space 40 contains a vacuum, and then the hole 72 may beblocked by the resin 74 or the like. By means of this, the closed space40 can be evacuated simply. With respect to the remaining construction,the effect, and the method of manufacture, this embodiment correspondsto the description of the first embodiment.

Fifth Embodiment

FIG. 5 shows a fifth embodiment of the optical device of the presentinvention. In this embodiment, the hole 72 is formed in the substrate 70(in detail, as described in the fourth embodiment), and the closed space40 is filled with transparent resin 60 (in detail, as described in thethird embodiment). The transparent resin 60 is also provided in the hole72, and by means of this, the hole 72 is blocked.

After previously evacuating the closed space 40, the closed space 40 maybe filled with the transparent resin 60 through the hole 72.Alternatively, the transparent resin 60 may be provided to seal theoptical element 10, and after adhering the flexible member 30, the foamwithin the closed space 40 may be removed through the hole 72.

With respect to the remaining construction, the effect, and the methodof manufacture, this embodiment corresponds to the description of thefirst, third, and fourth embodiments.

Sixth Embodiment

FIG. 6 shows a sixth embodiment of the optical device of the presentinvention. In this embodiment, the hole 72 is formed in the substrate 70(in detail, as described in the fourth embodiment), and the hole 72 isblocked by the flexible member 30. In more detail, the hole 72 isblocked on the surface of the substrate 70 that is opposite to theclosed space 40. The portion of the flexible member 30 blocking the hole72 is the portion adhered to the substrate 70. The hole 72 may be leftopen on the surface of the substrate 70 that is opposite to that of theclosed space 40, or may be filled with resin or the like, or may be usedas a hole for attachment to another element, or to position.

In the method of manufacture of this embodiment of the optical device,the flexible member 30 is first adhered to the substrate 70 so as not toblock the hole 72. Through the hole 72, the closed space 40 isevacuated, and the flexible member 30 is pulled in the direction of theclosed space 40, to obtain this embodiment. By means of this, by mereevacuation, the hole 72 can be blocked. With respect to the remainingconstruction, the effect, and the method of manufacture, this embodimentcorresponds to the description of the first and fourth embodiments.

Seventh Embodiment

FIG. 7 shows the seventh embodiment of the optical device of the presentinvention. In this embodiment, the hole 72 is formed in the substrate 70(in detail, as described in the fourth embodiment), and the hole 72 isblocked by a valve 80. The valve 80 is provided, for example, on thesurface of the substrate 70 opposite to that of the closed space 40. Thevalve 80 may be a film. The valve 80 is opened, the closed space 40 isevacuated through the hole 72, and the hole 72 is blocked by the valve80. With respect to the remaining construction, the effect, and themethod of manufacture, this embodiment corresponds to the description ofthe first and fourth embodiments.

It should be noted that FIG. 8 shows a digital camera 100, as an exampleof an embodiment of an electronic instrument to which the presentinvention is applied. The digital camera 100 has incorporates the abovedescribed optical device.

1. A method of manufacturing an optical device, comprising: mounting anoptical element on a substrate, the substrate having a penetrating hole;adhering a flexible member to the substrate so as to cover the opticalelement, to define a closed space between the substrate and the flexiblemember; evacuating the closed space through the penetrating hole;filling the closed space with transparent resin; and blocking the holewith the transparent resin.